This invention relates to vacuum cleaners, and more particularly to electronic control systems for vacuum cleaners.
Vacuum cleaners are typically provided with simple controls that allow the user to turn on and off the unit and perhaps to select the power to be applied to the suction motor to vary the level of suction. With the advent of lower costs for various electronic components, it has become feasible to provide additional features to the user using more sophisticated electronic control systems. In some instances, it has become possible to provide vacuum cleaners with microcontrollers to direct the operation of the unit. However, the functions that have been added have not always been those desired by the user. In other cases the added functionality provided by the addition of electronic controls has made vacuum cleaner control systems needlessly complex and overly expensive. For example, in canister vacuum cleaners two microcontrollers have sometimes been used to control the operation of the vacuum cleaner, one located in the canister and another in the handle that is connected to the vacuum cleaner hose and that contains the user controls. Other canister vacuum cleaners have supported various automatic modes of operation, but have either required that any optical dust sensor be located in the canister, which is cumbersome if the microcontroller used to control the operation of the vacuum cleaner is located in the handle, or have employed needlessly complex processing routines to determine the appropriate power setting of the suction motor. Still other vacuum cleaners have not allowed a user to easily select between a variety of bag change modes. While some previously known canister vacuum cleaners have had blow ports to which the vacuum cleaner hose could be attached, in has not been possible to control the operation of these vacuum cleaners using circuitry in a handle connected to the hose.
It would therefore be desirable to be able to provide a canister vacuum cleaner in which a microcontroller-based control unit contained in the handle of the vacuum cleaner is connected to the canister by a wired hose, which supports two-way communications between the control unit and the suction motor and various sensors contained in the canister, thereby allowing a single microcontroller to be used, simplifying the construction of the unit.
It would further be desirable to be able to provide a vacuum cleaner that can be placed in one of two user-selectable bag change modes: a maximum suction bag change mode, in which the vacuum cleaner shuts off when the pressure drop across the vacuum cleaner bag exceeds a predetermined threshold and a maximum fill bag change mode, in which the vacuum cleaner shuts off only after the pressure drop exceeds a higher threshold.
It also would be desirable to be able to provide a vacuum cleaner that has an optical dust sensor located in the handle of the vacuum cleaner, so that the vacuum cleaner can be placed in an automatic mode in which the power setting of the suction motor is adjusted based on the frequency with which dust particles are drawn past the sensor.
It also would be desirable to be able to provide a vacuum cleaner that has an optical dust sensor that is constructed from a light source and a photodetector, each of which is mounted in a lens unit having an integrally formed lens.
It also would be desirable to be able to provide a vacuum cleaner that has a blow port to which a vacuum cleaner hose can be attached and a control unit contained within a handle connected to the hose that contains circuitry for detecting when the hose is connected to the blow port.